Welding torch having collet and backcap adapted for securing engagement and method for operating same

ABSTRACT

A collet and a backcap are provided that are securable to each other. The collet and backcap may be adapted for threaded engagement. The collet and backcap may be utilized in a welding torch. A method of securing a collet to a backcap is provided. The method may comprise threading a threaded portion of the collet to a threaded portion of a backcap. A method of securing an electrode to a welding torch also is provided. The method may comprise securing a collet to a backcap. The method also may comprise threading the collet to the backcap.

BACKGROUND OF THE INVENTION

[0001] The present invention relates generally to the field of arcwelding systems, and more particularly to an arc welding torch adaptedto receive a cylindrical metal electrode.

[0002] TIG (Tungsten Inert Gas) welding (also known as gas tungsten arcwelding, GTAW, or HELIARC) is a type of arc welding process in which anelectric arc is maintained between a metal electrode and a metal object.The heat generated by the arc produces localized melting of the metalobject. The electrode, typically tungsten, is secured to a torch toenable a user to direct the electrode and establish the point of contactbetween the electrode and the object. TIG welding may be performed withor without the addition of a filler metal. Typically, the weld puddleand the area surrounding the weld puddle are protected from theatmosphere by an inert gas. The inert gas prevents rapid oxidation ofthe weld and the surrounding metal.

[0003] The electricity for the welding process is provided by a powersource through a welding cable coupled to the torch. Typically, thepower source is a constant voltage AC, DC, or a combination AC/DCsource. In addition, a TIG welding cable typically is adapted totransport the inert gas to the torch. Furthermore, the TIG weldingprocess typically generates a substantial amount of heat in theelectrode. Consequently, cooling fluid may be used to cool the torch.Thus, a welding cable for a TIG welding system may transportelectricity, gas, and cooling fluid.

[0004] The metal electrodes used in TIG welding typically are shapedlike long, cylindrical, metal rods. A TIG welding electrode typically issecured to a TIG welding torch by a collet, a backcap, and a collet bodyor gas lens. Gas lenses typically have screens disposed therein toprovide better gas flow characteristics than collet bodies. To securethe electrode to the welding torch, the electrode is inserted throughthe collet and collet body or gas lens. The collet body or gas lens isthreaded into a front portion of a threaded torch head disposed withinthe torch body. The backcap is threaded onto the rear portion of thetorch head. As the backcap is threaded onto the torch body, the backcapdrives the collet against the interior of the collet body or gas lens.The collet is adapted to pinch down on the electrode as the collet isdriven against an interior surface of the collet body or gas lens,thereby securing the electrode to the torch. In addition, the colletbody is adapted to enable gas to flow into the rear end of the colletbody around the electrode and out through holes in the side of thecollet body or gas lens. A nozzle is used to direct the gas towards theobject to be welded.

[0005] There are a number of problems associated with the use ofconventional collets, back caps, and collet bodies or gas lenses tosecure an electrode to a welding torch. One problem is that the colletmay be misaligned with the backcap and/or collet body during assembly.For example, the collet may not remain concentric with the backcap usingexisting techniques, thereby producing an uneven flow of gas around thecollet. In addition, loose parts, such as a collet, may be easily lostor dropped during assembly, increasing the time to complete the weldingtask.

[0006] A need exists for a technique to enable an electrode to beinstalled in a welding torch more easily than with existing collets andbackcaps. More specifically, a need exists for a system to enable acollet to be secured to a backcap. In addition, there is a need for atechnique for securing an electrode to a welding torch withoutmisalignment of the collet and backcap and to provide better shieldinggas flow around the collet.

SUMMARY OF THE INVENTION

[0007] The present technique provides a collet and backcap that areadapted to be secured together. The collet and backcap may be adaptedfor threaded engagement. The collet and backcap may be utilized in awelding torch of a welding system.

[0008] In accordance with another aspect of the present technique, amethod of securing a collet to a backcap is provided. The method maycomprise threading a threaded portion of the collet to a threadedportion of a backcap.

[0009] In accordance with another aspect of the present technique, amethod of securing an electrode to a welding torch is provided. Themethod may comprise securing a collet to a backcap. The method also maycomprise threading the collet to the backcap.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The foregoing and other advantages and features of the inventionwill become apparent upon reading the following detailed description andupon reference to the drawings in which:

[0011]FIG. 1 is a perspective view of a welding system, according to anexemplary embodiment of the present technique;

[0012]FIG. 2 is an exploded view of a welding torch, according to anexemplary embodiment of the present technique;

[0013]FIG. 3 is an elevational view of a backcap, according to anexemplary embodiment of the present technique;

[0014]FIG. 4 is an elevational view of a collet, according to anexemplary embodiment of the present technique;

[0015]FIG. 5 is a detailed exploded view, illustrating the assembly of aportion of the welding torch, according to an exemplary embodiment ofthe present technique; and

[0016]FIGS. 6 and 7 are cross-sectional views illustrating the operationof the collet in securing an electrode to the welding torch, accordingto an exemplary embodiment of the present technique.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

[0017] Referring generally to FIG. 1, a TIG welding system isillustrated, as represented generally by reference numeral 10. However,the present technique may be utilized on other welding systems. Thewelding system 10 comprises a power supply 12, a welding torch 14, awelding cable 16, and a return cable 18. The power supply 12 may be aconstant voltage AC, DC, a combination AC/DC source, or some other typeof power supply. The welding cable 16 electrically couples the weldingtorch 14 to one terminal of the power supply 12. The return cable 18 iscoupled to a second terminal of the power supply 12. In the illustratedembodiment, the return cable 18 has a clamp 20 that is adapted to secureand electrically couple the return cable 18 to a workpiece 22 to bewelded. The welding torch 14 is adapted to receive an electrode 24. Whenthe electrode 24 comes in close proximity to or touches the material 22to be welded, an electric circuit is completed from one terminal of thepower supply 12, through the welding cable 16, the electrode 24, theworkpiece 22, the work clamp 20, and the return cable 18 to a secondterminal of the power supply 12.

[0018] In the illustrated embodiment, in addition to electricity, gasfrom a gas source is coupled to the torch 14. In the illustratedembodiment, the gas source is a gas cylinder 26 coupled to the powersupply 12. In the illustrated embodiment, the gas is coupled from thepower supply 12 to the torch 14 through the welding cable 16. In thisembodiment, the power supply 12 has numerous controls 28 to enable auser to control various operating parameters of the power supply 12,such as the output amperage.

[0019] In the illustrated embodiment, the welding torch 14 has a handle30 that is adapted to receive the welding cable 16. The handle 30 alsois adapted to be held by a user to direct the operation of the torch 14.The welding torch 14 also has a torch body 32 that is adapted to holdthe electrode 24 and direct the inert gas towards the target material22. In this embodiment, the torch 14 also has a back cap 34 to seal theend of the torch body 32 opposite the electrode so that the gas does notleak out of the torch body 32. Various lengths of back caps may be usedto enable the torch body to receive electrodes of various lengths. Inaddition, a nozzle 36 is secured to the front end of the welding torch14 to direct gas toward the workpiece 22.

[0020] Referring generally to FIG. 2, an exploded view of welding torch14 is illustrated. An insulator 38 is provided for electrical isolation.In the illustrated embodiment, a collet 40 and a collet body 42 areprovided to secure the electrode 24 to the torch body 32. The collet 40and collet body 42 cooperate with the backcap 34 to secure the electrode24 to the torch body 32. In the illustrated embodiment, the collet 40and backcap 34 are adapted for threaded engagement, rather thanabutment. However, a device other than a collet body 42 may be used withthe collet 40 to secure the electrode 24 to the torch body 32. Forexample, a gas lens may be used with the collet 40 to secure theelectrode 24 to the torch body 32.

[0021] Referring generally to FIGS. 2 and 3, the illustrated backcap 34has a threaded inner portion 44 that is adapted to receive acorresponding threaded outer portion 46 of the collet 40. The backcap 34also has a threaded outer portion 48 for securing the backcap 34 to thetorch body 32. In the illustrated embodiment, the backcap 34 has a capportion 49 that is adapted to receive the electrode 24 and to form aseal with the torch body 32. The backcap 34 has a chamber 50 that isadapted to enable a welding electrode 24 to extend into the cap portion49. Preferably, the cap portion 49 has ergonomic features to facilitatemanual rotation of the backcap 34. In the illustrated embodiment, thebackcap 34 has a sealing member 52 to enable the backcap 34 to form aseal with the torch body 32 to prevent gas from escaping via the backcap34.

[0022] Referring generally to FIGS. 2 and 4, the collet 40 has a chamber54 that extends through the collet 40 to enable an electrode 24 toextend through the collet 40. In addition, the collet 40 has a pluralityof slits 56 that extend along a length of the collet 40 to enable thecollet 40 to be compressed to narrow the chamber 54. A portion 58 of thechamber 54 is adapted to grip the electrode 24 as the collet 40 iscompressed. The collet 40 is compressed when the collet 40 and colletbody 42 are driven into abutment. In the illustrated embodiment, thecollet 40 has a tapered end surface 60 to facilitate compression of thecollet 40 during abutment with the collet body 42.

[0023] Referring generally to FIG. 5, an electrode 24 is secured to thetorch body 32 by the cooperation of the backcap 34, the collet 40, andthe collet body 42. However, as discussed above, a gas lens or a deviceother than the collet body 42 may be utilized in accordance with thepresent technique. A torch body 32 typically has a torch head 61 with afully threaded inside diameter. The torch head 61 has a front threadedportion 69 to secure the collet body 42 or gas lens to the torch head 61and a rear threaded portion 63 for securing the collet 40 and backcap 34assembly to the torch head 61. The collet body 42 has a first threadedouter portion 62 that is adapted for securing the collet body 42 to thetorch head 61 of the torch body 32. In addition, the torch head 61 alsois adapted to receive the threaded outer portion 48 of the backcap 34.In addition, the collet body 42 has a second threaded portion 64 toenable the nozzle 36 to be secured to the collet body 42. In addition,an electrically insulating polymeric material 65 is disposed over mostof the torch body 32.

[0024] Referring generally to FIGS. 6 and 7, the collet body 42 has achamber 66 that extends through the collet body 42. The chamber 66 isadapted to receive the collet 40 and to enable gas to flow through thecollet body 42 in the region of the chamber 66 around the collet 40. Theillustrated collet body 42 also has a plurality of exit holes 68 toenable gas to exit from the chamber 66 and to flow through the nozzle36. The chamber 66 of the collet body also has a surface 70. The taperedsurface 70 of the collet body 42 is adapted to abut the tapered endsurface 60 of the collet 40 as the collet 40 and collet body 42 aredriven into engagement and thereby apply a compressive force to thecollet 40. The threaded portion 63 of the torch body 32 enables relativemovement between the collet body 42 and the backcap 34 to enable thecollet 40 and collet body 42 to be driven into abutment.

[0025] To secure an electrode 24 to the torch body, the electrode 24 isdisposed through the collet body 42 and collet 40 and the collet 40 isthreaded to the backcap 34. As discussed above, the backcap 34 has athreaded inner portion 44 that is adapted to receive a threaded outerportion 46 of the collet 40. By threading the collet 40 to the backcap34, a consistent concentric arrangement of the collet 40 and backcap 34is obtained. The consistent arrangement of the collet 40 and backcap 34produces a uniform region for gas to flow through the torch body 32,thereby providing uniform characteristics in the flow of gas 67 throughthe torch body 32. The backcap 34 also has a threaded outer portion 48that enables the backcap 34 to be secured to the torch body 32.

[0026] The electrode 24 may be disposed through the collet 40 before orafter the collet 40 is secured to the backcap 34. In addition, theelectrode 24 may be disposed through the collet body 42 before or afterthe collet body 42 is secured to the torch body 32. As the backcap 34 isthreaded to the torch body 32, the backcap 34 urges the collet 40towards the collet body 42, as represented by arrow 72. When the collet40 engages the collet body 42, the collet 40 is compressed by the colletbody 42, as represented by the arrows 74, causing the collet 40 to gripthe electrode 24.

[0027] Preferably, the backcap 34 is threaded onto the torch body 32 tourge the collet 40 against the collet body 42. However, the collet body42 may be threaded onto the torch body 32 to urge the collet body 42against the collet 40. In addition, the collet 40 may be adapted with athreaded inner portion that is adapted to receive a correspondingthreaded outer portion of the backcap 34. Thus, the collet 40 also maybe adapted with a threaded outer portion 48 for securing the collet 40to the torch body 32.

[0028] The techniques provided above enable a collet to be secured to abackcap, rather than simply being held by a loose abutment between abackcap and a collet body. Because the collet is secured to the backcap,the alignment of the collet within the torch body is more consistentand, thus, there is a more consistent flow of gas through the torch bodyaround the collet. In addition, the assembly of the torch is simplifiedbecause the collet may be secured to the backcap. Therefore, thepossibility of dropping a loose collet is greatly reduced. Furthermore,the process of changing from one electrode to another is facilitatedbecause the process of changing the collets is facilitated by having theability to secure the collet to the backcap.

[0029] While the invention may be susceptible to various modificationsand alternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, it should be understood that the invention is not intended tobe limited to the particular forms disclosed. Rather, the invention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the followingappended claims.

What is claimed is:
 1. A welding torch, comprising: a torch body; acollet having a first threaded portion, the collet being adapted toreceive a welding electrode and to cooperate with a second member tosecure the welding electrode to the torch body; and a backcap having asecond threaded portion adapted for threaded engagement with the firstthreaded portion of the collet, the backcap being securable to the torchbody.
 2. The welding torch as recited in claim 1, wherein the firstthreaded portion is disposed on an outer portion of the collet and thesecond threaded portion is disposed on an inner portion of the backcap.3. The welding torch as recited in claim 1, wherein the backcap andtorch body are adapted for threaded engagement.
 4. The welding torch asrecited in claim 1, wherein the collet is adapted with a chambertherethrough to enable the electrode to extend through the collet. 5.The welding torch as recited in claim 4, wherein the collet is adaptedto be compressed against the welding electrode as the collet is urgedagainst the second member.
 6. The welding torch as recited in claim 5,wherein the collet is adapted with a plurality of slits extendingbetween an outer surface of the collet and the chamber through thecollet.
 7. The welding torch as recited in claim 5, wherein the colletcomprises a tapered surface adapted to urge the collet into compressionwhen abutted with the second member.
 8. The welding torch as recited inclaim 1, wherein the welding electrode is a cylindrical metal electrode.9. The welding torch as recited in claim 1, wherein the torch bodycomprises a threaded portion adapted for threaded engagement with thebackcap.
 10. The welding torch as recited in claim 1, wherein thewelding torch is adapted for use with a TIG welding system.
 11. A colletfor a welding torch, comprising: a first portion adapted for threadedengagement with a threaded member; and a second portion adapted tocapture a welding electrode.
 12. The collet as recited in claim 11,wherein the first and second portions are adapted to receive theelectrode therethrough.
 13. The collet as recited in claim 11, whereinthe first portion is adapted with an external thread adapted forthreaded engagement with an internal thread of the threaded member. 14.The collet as recited in claim 11, wherein the second portion is adaptedto squeeze the welding electrode as the collet is abutted against asecond member.
 15. The collet as recited in claim 14, wherein the secondportion is adapted with at least one slit extending along a length ofthe second portion to enable the second portion to be compressed. 16.The collet as recited in claim 11, wherein the threaded member is athreaded backcap adapted to receive a portion of the welding electrode.17. The collet as recited in claim 11, wherein the welding electrode isa cylindrical metal electrode.
 18. A backcap for a welding torch,comprising: a first threaded portion adapted for threaded engagementwith the welding torch; and a second threaded portion adapted forthreaded engagement with a collet adapted to secure an electrode to thewelding torch.
 19. The backcap as recited in claim 18, wherein the firstthreaded portion has an inner thread adapted for threaded engagementwith an outer thread of the collet.
 20. The backcap as recited in claim18, wherein the back cap is adapted to receive a portion of a weldingelectrode.
 21. The backcap as recited in claim 18, wherein the weldingelectrode is a cylindrical metal electrode.
 22. The backcap as recitedin claim 18, wherein the back cap is adapted to form a seal with thetorch body.
 23. A method of securing an electrode to a welding torch,comprising the act of securing a collet adapted to capture the electrodeto a backcap adapted to secure the collet to the welding torch.
 24. Themethod as recited in claim 23, wherein securing comprises threading athreaded portion of the collet to a threaded portion of the backcap. 25.The method as recited in claim 23, wherein threading comprises threadingan external thread of the collet into an internal thread of the backcap.26. The method as recited in claim 23, further comprising: disposing theelectrode through a first member securable to the welding torch;disposing the welding electrode through the threaded collet; securingthe first member to the welding torch; and securing the backcap to thewelding torch.
 27. The method as recited in claim 26, wherein securingthe backcap to the welding torch comprises threading the backcap to thewelding torch.
 28. The method as recited in claim 26, wherein threadingthe backcap to the welding torch wedges the threaded collet between thefirst member and the electrode.
 29. The method as recited in claim 28,wherein securing the backcap to the welding torch comprises compressingthe collet against the welding electrode.
 30. A collet for a weldingtorch, comprising: a first portion adapted for threaded engagement witha first member securable to a welding torch head; and a second portionadapted to be compressed against a welding electrode by a second memberto secure the welding electrode to the welding torch head.
 31. Thecollet as recited in claim 30, wherein the first and second portionshave a chamber extending therethrough to enable the welding electrode toextend through the collet.
 32. The collet as recited in claim 31,wherein the second portion has a plurality of slits in the secondportion extending through the second portion between an outer surface ofthe second portion and the chamber.
 33. The collet as recited in claim30, wherein the first portion is adapted with threads on an exteriorsurface of the first portion.
 34. The collet as recited in claim 30,wherein the welding electrode is a cylindrical metal electrode.
 35. Awelding torch, comprising: means for securing a collet adapted tocapture an electrode to a backcap adapted to secure the collet to thewelding torch.
 36. The welding torch as recited in claim 35, furthercomprising: means for securing a first member adapted to abut the colletto the welding torch; and means for securing the backcap to the weldingtorch.
 37. The welding torch as recited in claim 35, wherein the weldingtorch is adapted to direct gas through the welding torch.
 38. Thewelding torch as recited in claim 37, wherein the electrode is acylindrical metal electrode.
 39. A welding system, comprising: a powersource; and a welding torch electrically coupleable to the power source,the welding torch comprising: a torch head; a first member securable tothe torch head; a collet adapted to cooperate with the first member tosecure an electrode to the torch head, the collet having a threadedportion; and a backcap having a first threaded portion adapted forthreaded engagement with the torch head and a second threaded portionadapted for threaded engagement with the threaded portion of the collet.40. The system as recited in claim 39, wherein the electrode is acylindrical metal electrode.
 41. The system as recited in claim 40,wherein the backcap is adapted to drive the collet into abutment withthe first member to compress the collet against the electrode.
 42. Thesystem as recited in claim 41, wherein the torch head is adapted todirect gas through the torch head around the collet.
 43. The system asrecited in claim 39, wherein the welding system is a TIG welding system.